Automatic electrical controller for air-compressors.



P. D. AOKERMAN. AUTOMATIC ELECTRICAL CONTROLLER FOR AIR COMPRESSORS.

APPLICATION FILED MAY 17. 1905.

PATEN'I'ED JAN. 2, 1906.

3 SHEETS-SHEET 1.

ATTORNEYS N0. 809,083. PATENTED JAN. 2, 1906. P. D. AGKBRMAN.

3 SHEETS-SHEET 2.

W/T/VESSES: INVENTOR %4 Q.@ I FRED a HOKERMfl/V W By W ATTORNEY?PATENTED JAN. 2, 1906.

. F. D. AGKERMAN.

AUTOMATIC ELECTRICAL CONTROLLER FOR AIR GOMPRESSORS.

APPLICATION FILED MAYl'I, 1905.

N a n Q N m w E H mm ugfivnh EQTBJAJJMPAE M g 5 W 0 i I I .H h, l N Nwmfi R a ATTORNEYS the cylinder (see Figs. 2 and 5) is secured a Verticalbracket or bent arm 27, carrying a vertical tube 28. Within this tube arod or plunger 29 is adapted to slide, the same having a lateral pin 30working in a vertical slot in the tube 28, so that the rod is preventedfrom rotating. The lower end of the rod is provided with a roller'31,which is adapted to seat in the depressions or cavities 26, beforereferred to. A cylindrical screw 32, having a milled head, is applied tothe upper end of the tube 28, which is screw-threaded internally at thatpoint. Between the said screw and the slidable plunger 29 is arranged aspiral spring 33. It is apparent that by rotating the screw 32 thepressure of the same upon the spring 33 and the compression of thelatter may be regulated, as desired, with the corresponding efiect ofvarying the pressure of the roller 31 in the depressions 26 of thecylinder 18.

As illustrated in Fig. 4c, the D-valve 3 is held to its seat by a spring34. An exhaustport 35 is provided in the air-chest 2 adjacent to theport 36,that communicates with the pipe 11, which connects the air-chestwith the lower air-cylinder 12.

Let it be supposed that the switch 22 is closed and that the motor isoperating the pump to compress air. The valve 3 would then be, as shownin Fig. 4, connecting the left end of the cylinder 12 to the exhaustthrough ports 36 and 35. There being no pressure at the left of piston13, the spring 17 would be fully expanded. As the air is compressed thepiston 6 is gradually moved to the right against the tension of thespring 10, carrying valve 3 with it. WVhen the pressure is sufiicientlygreat, the port 26 is disconnected from the port 35 and connected to theinterior of valve-chest 2, as shown in Fig. 1. Thereby air is admittedto the left of the cylinder 12, forcing piston 13 to the right againstthe pressure of spring 17 and compressing spring 19 until said latterspring overcomes the retaining influence of spring 33 and latch 31 andopens switch 32 with a snap action, whereby operation of the motor andair-compressor is arrested. Fig. 7 illustrates the compression of thespring 19 in casing 18 just previous to release of the latter from thespring-actuated latch 21, and Fig. 2 shows the position of said casingafter such release. As air is drawn off from the storage-tank theairpressure falls in chamber 2, the spring 10 gradually moves piston 6and valve 3 to the left, so as to cover ports 35 36, or at minimumpressure disconnecting port 36 from valve-chest 2 and connecting it toexhaustport 35, so that air escapes from cylinder 12 and piston 13therein moves to the left, the switch 22 is closed, and the motoroperates the pump to compress air again. This cycle of operationcontinues to maintain the pressure between certain maximum and minimumlimits, which are determined by the adjustment of spring 10. It will beunderstood that when the piston 13 of cylinder 12 thus resumes itsnormal position (shown in Fig. 6) the slidable casing 18 and itscontained spring 19 are also drawn back to normal position by engagementof the pin 21 of bar 15 with the adjacent head of, said casing. In thismovement the spring 19 simply slides with the casing and has no functionsave in producing the automatic snap action before described.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The improved automatic controller for the purpose specified,comprising a valve-chest and valve, an air-cylinder and a slidablepiston contained therein and connected with said valve, a spring foropposing the movement of the piston in one direction, a secondaircylinder having a spring-pressed piston, an air-conductor connectingsuch second cylinder with the valve-chest, a slidable bar connected withthe last-named piston, a casing applied to and slidable on said bar, aspring contained within the said casing and applying pressure between itand the bar, an electrical switch one member of which is connected withthe casing, and spring locking and release mechanism connected with thecasing for holding it normally immovable and the switch normally closeduntil a certain predetermined air-pressure is accumulated, substantiallyas described.

2. The improved controlling apparatus for the purpose specified,comprising two aircylinders and pistons therein having springs foropposing movement in one direction, an air-chamber having a slidableValve which'is connected with one of said pistons, a pipe connecting theair-chamber with a second cylinder, and an automatic locking andreleasing mechanism connected with the piston of the second cylinder andcomprising a slidable bar, a device that is slidable on said bar andprovided with abutments or shoulders, a spring arranged between saiddevice and a projection on said bar, and a spring-pressed latch adaptedto engage with and automatically release said device, substantially asshown and described.

3. In a controller for the purpose specified, the combination with anair-cylinder, a piston slidable therein, a slidable bar extendingtherefrom and a guide in which said bar works, a casing applied to suchbar and slidable thereon, a spring interposed between one portion ofsuch casing and a stop on the bar, the casing having a top portionprovided with depressions at opposite ends, a locking and releasingmechanism comprising aspringactuated plunger having at its free end aroller adapted to enter said depressions and thus lock the casing untilthe pressure of the plunger-spring is overcome, and a switch included ina motor-circuit and adapted to be broken when the air-pressure reaches acertain predetermined degree and the locking mechanism releases thecylinder which it engages, substantially as described.

4. In a controller for the purpose specified, the combination with anair cylinder and means for connecting it with an air-storage tank, of apiston which is slidable in said cylinder, a spring applied thereto foropposing movement in one direction, a bar connected with the piston andslidable therewith, a cas ing applied to the bar and slidable thereon, aspring inclosed by the casing and arranged between one end thereof and astop on the bar, a casing having on its upper side engaging shoulders, alocking and releasing mechanism comprising a vertical tube having a FREDD. 'ACKERMAN.

Witnesses:

OSCAR WILLIAMS, W. G. WATKINS.

